CVE-2021-37909: WriteRegistry function in TSSServiSign component does not filter and verify users’ input, remote attackers can

Q: How do I fix CVE-2021-37909?

tssservisignadapter: upgrade to newer than 1.0.20.0316. Exact commands for each OS are on this page.

Q: Is CVE-2021-37909 being exploited?

CVE-2021-37909 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2021-37909 affect?

CVE-2021-37909 affects tssservisignadapter. Severity is critical (CVSS 9.8). WriteRegistry function in TSSServiSign component does not filter and verify users’ input, remote attackers can rewrite to the registry without permissions thus perform hijack attacks to execute arbitrary code.

Q: How urgent is CVE-2021-37909?

Priority 60/100. Critical severity; Remotely exploitable, no login, no user action

This week

CRITICAL 9.8REMOTEUPGRADE

CVE-2021-37909 is a critical-severity flaw (CVSS 9.8) affecting tssservisignadapter. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

WriteRegistry function in TSSServiSign component does not filter and verify users’ input, remote attackers can rewrite to the registry without permissions thus perform hijack attacks to execute arbitrary code.

Why this priority

Critical severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	2.0% (top 19%)
CISA exploited list	No
Weakness	CWE-20
Published	2021-09-15
Last modified	2026-06-17

Publisher (CNA): TWCERT/CC · Vendor: tssservisignadapter project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-09-15 19:15 UTCPublished CVE record published
2026-06-17 04:01 UTCUpdated Record last modified

tssservisignadapter project tssservisignadapter UPGRADE

Affected: <= 1.0.20.0316

Fixed in: newer than 1.0.20.0316

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy tssservisignadapter || rpm -q tssservisignadapter || tssservisignadapter --version

2. UPGRADE to newer than 1.0.20.0316 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade tssservisignadapter

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade tssservisignadapter

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-37909?

tssservisignadapter: upgrade to newer than 1.0.20.0316. Exact commands for each OS are on this page.

Is CVE-2021-37909 being exploited?

CVE-2021-37909 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-37909 affect?

CVE-2021-37909 affects tssservisignadapter. Severity is critical (CVSS 9.8). WriteRegistry function in TSSServiSign component does not filter and verify users’ input, remote attackers can rewrite to the registry without permissions thus perform hijack attacks to execute arbitrary code.

How urgent is CVE-2021-37909?

Priority 60/100. Critical severity; Remotely exploitable, no login, no user action

References

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